Routing of data transmission connection

ABSTRACT

A problem with known data transmission networks is that the connection of the terminal equipment to the data transmission network is not flexible. The user must himself actively perform the choice and connection of access as well as it registration with the network nodal point. The invention concerns a method and an arrangement for routing a data transmission connection between terminal equipment and a host over a data transmission network, which network includes at least two access points for connecting the terminal equipment to the data transmission network. The method is characterized in that a least one criterion is established for the choice of access point, the access points are estimated according to said criteria, at least one access point meeting the criteria is chosen, and the data transmission traffic is connected through the chosen at least one access point.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a Continuation of application Ser. No. 09/623,928, filed Sep. 8,2000, which is a national stage of International ApplicationPCT/FI99/00174, filed Mar. 5, 1999.

FIELD OF THE INVENTION

The invention concerns routing of a data transmission connection betweena piece of terminal equipment and a host over a data transmissionnetwork.

TECHNICAL BACKGROUND

Mobile use of various personal computers, e.g. PDA (Personal DigitalAssistant) and intelligent telephones, has become increasingly popular.Using such terminal equipment the user is in connection with the host,both in the office and outside the office. Some modern user interfacesfor terminal equipment, such as Windows 95, allow connection anddisconnection of so-called plug-and-play accesses even while theapplication is running.

It is known in the state of the art to choose the routing at nodalpoints of a network. FIG. 1 in the appended drawing shows how a piece ofterminal equipment is connected through an intermediary network(Internet) to a host in a known manner, e.g., when moving outside theoffice in situation 1, terminal equipment TE connects with the AP1(Access Point). In the messages which it sends, the terminal equipmentuses as source address the address reserved by the access point for theterminal equipment. A node wishing to be in connection with the terminalequipment will for its part use said address as destination address formessages which it sends. When the access point is changed, this addresswill be exchanged, e.g. in the situation 2 shown In FIG. 1 for theaddress reserved by access point AP2. By using e.g. the Mobile IPprotocol, the access point used currently by the uses may be registeredin the HA (home agent), which allows use of the same addressirrespective of the access point. However, the user must choose manuallythe access point to be used at each time. It is not possible in thisarrangement to exchange the access point automatically for anotheraccess point while terminal equipment TE is moving, e.g. to replace AP1with AP2, but the terminal equipment must itself actively connect andregister with anew access point in order to bring about the connection.The user can be connected with one access point at a time.

The connection from terminal equipment TE is set up using the availableaccess. Various network accesses are e.g. the Ethernet or IR (infra-red)at the office or the GSM (Global System for Mobile Communications) dataaccess, especially the GPRS (General Packet Radio Service) access,outside the office. One generally used way of access is by connecting aPCMCIA access card to terminal equipment TE. The user may remove andconnect these accesses as he desires, whereby the connection is set upby way of the access which is connected at each time. Several cards mayalso be connected at the same time to terminal equipment TE, but herebyonly one of them is used, e.g. the access which was connected first tothe terminal equipment, and the access is not exchanged automaticallyfor another while the connection is in use, even if the connectionthrough the used access is lost.

It is a problem with state-of-the-art accesses that the connection ofthe terminal equipment with the data network is not flexible. The usermust himself actively carry out the choice of the access to be used aswell as its connection and registration with the network nodal point. Inaddition, when exchanging the access it is sometimes necessary to dosethe application and to restart the system in order to begin using a newaccess.

SUMMARY OF THE INVENTION

An objective of this invention is to bring about a flexible system usingdifferent network accesses and a method for routing a data transmissionconnection between the terminal equipment and the host.

This new type of routing a data transmission connection is achieved bymethods according to the invention which are characterised by what issaid in independent claims 1 and 15. Preferable embodiments of themethods are presented in the dependent claims.

In addition, the invention concerns arrangements, which according to theinvention are characterised by what is said In independent claims 26, 28and 30.

The invention is based on the idea that the first routing of theconnection between the terminal equipment and the host is carried out inthe terminal equipment and/or in a gateway exchange located between theterminal equipment and the host, according to criteria established inadvance. In a first alternative embodiment of the invention, a routerlocated in the terminal equipment monitors the access points currentlyavailable according to pre-established criteria for the routing of thedata transmission. Based on the results of this monitoring, the routerof the terminal equipment will route the data transmission traffic byway of at least one access point meeting the criteria in the desiredmanner. According to the criteria set up in the different embodiments,the router of the terminal equipment selects at least one routingalternative from at least two different access points and/or divides thetraffic proportioned between at least two access points. The terminalequipment connects the chosen access/the chosen accesses with theapplication of the terminal equipment, preferably transparently from theviewpoint of the application and the user. Of the routing alternativesone may also choose more than one access for connection to theapplication simultaneously, whereby the data transmission will takeplace through several transmission connections, e.g. in order to ensurethe data transmission. Criteria established in advance are e.g. thetransmission capacity, transmission delays, transmission errors, datasecurity and/or the costs of data transmission. The application may alsoset up these criteria. In the other alternative embodiments of theinvention, the first routing is performed to the terminal equipmentaccording to pre-established criteria in the terminal equipment and inthe gateway exchange or only in the gateway exchange.

It is an advantage of such a method that it allows to choose the accesswhich is most advantageous for the user, e.g. the cheapest access or onewhich gives the best performance.

It is another advantage of the method according to the invention thatchange of the access and use of accesses can be carried out in a mannerwhich is transparent to the user and/or the application, keeping up anessentially continuous connection. No changes need be made in existingconnecting methods.

It is also an advantage of the method according to the invention that itallows data security for the data transmission connection from one endto the other as well as data compression when required.

It is an advantage of the arrangement according to the invention that itdoes not require any special application or any changes tostate-of-the-art applications, but it can be used when using existingapplications. Nor need any changes be made in existing access points orin the transmission network:

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in greater detail in connection withpreferable embodiments and referring to the examples shown in FIGS. 2-6of the appended drawings, wherein:

FIG. 1 shows a state-of-the-art connection of a piece of terminalequipment to a host over a data transmission network;

FIG. 2 shows a connection of a piece of terminal equipment to a hostover a data transmission network In accordance with the invention;

FIG. 3 is a flow chart of a primary embodiment of the invention;

FIG. 4 shows a case by way of example of a primary embodiment of theinvention wherein data packages are relayed through network accesspoints in accordance with the invention;

FIG. 5 is a flow chart of a secondary embodiment of the method accordingto the Invention; and

FIG. 6 shows the structure of a piece of terminal equipment according tothe invention at protocol level.

DETAILED DESCRIPTION OF THE INVENTION

The present invention may be applied In connection with any datatransmission system. The invention will be described in greater detailhereinafter in the light of preferable embodiments and referring to thefigures in the appended drawings. As used in this application, accesspoint refers to a general connection point in a data transmissionnetwork to which the terminal equipment may connect itself in order toset up an access to the data transmission network.

FIG. 2 shows the structure of an access network in accordance with theinvention. The figure shows three alternative routes R1, R2 and R3 fromterminal equipment TE to a host by way of an intermediary Internetnetwork and gateway exchange GW. According to the invention, one canhereby choose between several alternative routes, in the case shown inFIG. 2 there are three routes, of which at least one access at a time ischosen for use by the terminal equipment. The accesses connected to theterminal equipment may be e.g. Ethernet, IR and GSM data accesses. Inthe terminal equipment an APPL application is running, for the use ofwhich the access is chosen. When required, the traffic between theterminal equipment and the host may be compressed and/or encrypted.

In the following, the invention will be described in greater detail inthe light of a primary embodiment of the invention and referring to FIG.3, which is a flow chart of a primary embodiment of the method accordingto the invention. At point 30 in FIG. 3 at least one criterion isestablished for the choice of access. At point 31 the available accessesare monitored with the aid of their pre-established criteria accordingto the invention. This monitoring may be performed e.g. by monitoringeach available access constantly or at certain intervals of time. Atpoint 34 a check is made on whether the pre-established criteria havebeen met. There may be one criterion or more criteria at the same time,whereby in the case of several criteria the choice requires that allestablished criteria are met. Removal from use of a current access maybe such a criterion which will trigger off an exchange of access. Thecheck on criteria at point 34 may also be carried out by monitoring thequality of data transmission. After the condition 34 is fulfilled, achoice is made at point 36 of the access indicated by the criteria, andhereafter the traffic will be routed through this new access.

In a primary embodiment of the method according to the invention it isalso possible to choose more than one access for connection at the sametime between the terminal equipment and the host. FIG. 4 shows by way ofexample a network structure wherein data is transmitted along at leasttwo different routes between terminal equipment TE and the host. In FIG.4 a gateway exchange transmits to terminal equipment TE the datapackages which it has received from the host both along route R1 andalong route R2. Gateway exchange GW may number the data packages beforethe transmission, as the marks indicate in FIG. 4. Due to transmissionerrors, terminal equipment TE in the example shown in FIG. 4 receivesthrough access R1 numbered packages I, III, IV and through access R2packages I, II, III. By combining these packages received alongdifferent routes terminal equipment TE receives the entire transmittedseries of packages. Owing to the numbering of the data packages,terminal equipment TE is able to screen away redundant packages, in thecase shown in FIG. 4 second packages I and III, which are thus receivedboth through access R1 and through access R2. The numbering of packagesalso makes it possible to determine the characteristics of the differentaccesses by comparing the numbering of packages received through thesedifferent accesses. In FIG. 4 access R3 is a standby access and thisaccess point is monitored in accordance with the invention with the aidof the access choice criteria, as was described above in connection withthe primary embodiment of the invention. Should terminal equipment TE inthe case shown in FIG. 4 decide to change the access to access point R3,terminal equipment TE after its change of access point may inform thenetwork what number the data package must have which is to be sent next.Gateway exchange GW need not necessarily send all data packages alongeach available route.

According to the functionality of the primary embodiment of theinvention, the terminal equipment may first be connected to the host byan Ethernet access (R1), whereby the data is routed through this access.When the uses removes the Ethernet access card, a message of this isrelayed to the terminal equipment's router, which according to theinvention will look for a new alternative route, on which the operationcan be continued. Any data packages arriving for transmission while anew route is being sought are placed in a queue to wait, until a newroute is found. The search for a new route may also be carried outbeforehand while the connection in use is still working. When a newroute is found, e.g. an IR access (R2), the operation is continuedthrough the IR access, until it is time for the IR access to beabolished. The router again receives information on the removal of theaccess and it will seek a new access to carry on the operation. When theuser connects to a GSM data service, the router will route the datatransmission by way of the GSM data access (R3). In the routing exampleaccording to the invention described above, the transmission connectionis essentially formed by a continuous network access, which may bemomentarily disconnected only during the time when a new route is soughtand connected for use.

FIG. 5 is a flow chart of a secondary embodiment of the method accordingto the invention. In the secondary embodiment of the invention, thetraffic is divided between at least two accesses according topre-established criteria. At point 50 at least one criterion isestablished for the choice of transmission capacity of the access. Atpoint 51 a check is made of the available accesses with the aid of thesepre-established criteria according to the invention. This check may becarried out e.g. by monitoring each available access constantly or atcertain intervals. At point 54 a check is made of whether the situationof the accesses has changed from the view-point of the criteria. Acriterion triggering off a new division of the traffic may be e.g. sucha change of the transmission capacity available in the access that itexceeds or falls short of a certain value or several different values.The check of criteria at point 54 may also be carried out by monitoringthe quality of the data transmission. After the condition 54 isfulfilled, the traffic is divided at point 56 between the accesses inthe proportion indicated by the result of the criteria check, e.g. sothat a certain part of the traffic is relayed through one access and theremaining traffic through another access.

The primary and secondary embodiment of the invention which weredescribed above can also be combined, whereby a choice of at least twoaccesses at a time is performed in the router in accordance with theprimary embodiment of the invention, while the division of trafficbetween the chosen accesses is performed. In accordance with thesecondary embodiment of the invention. Hereby the criteria for thechoice of access and the criteria for division of the traffic betweenaccesses may be criteria which are separate from one another.

As criteria mentioned above one may establish e.g. the costs of datatransmission, so that a certain access is chosen, e.g. a GPRS access, oras much as possible of the traffic is always transmitted in this accesswhen no such access is available where the operation would be cheaper,such as, e.g. Ethernet. Other criteria may be e.g. the transmissioncapacity, transmission delays, data security or transmission errors,whereby the criterion is fulfilled e.g. when some other access is betterthan the access in use as regards the established criterion or it isfound that the access in use is poor according to one criterion. Herebysuch an access may be chosen as the new access which fulfils the secondcriterion, or the relaying of traffic can be moved more to the accessfulfilling the second criterion. The transmission capacity criterion canbe used for choosing and putting into use a new access point e.g. when anew application starts up and sets up a connection requiring moretransmission capacity. Several criteria of choice may be established atthe same time, e.g. any combination of the criteria of choice mentionedabove. The criteria of choice are preferably established so that thetraffic can be directed to the new access before the transmissioncapacity of the old access is removed.

In a third embodiment of the invention, at least some of the accesschoice criteria are learning criteria, which are established inaccordance with the user's repeating activity. Hereby the criteria ofchoice are e.g., the time and/or the place, where the terminal equipmentis connected to the first access point. If the terminal equipment movesrepeatedly along the same geographical route, it is possible to foreseethe need to change access point and to connect the new access point inadvance to operate with the terminal equipment. Hereby, e.g., in asituation of access change the terminal equipment is in connectionthrough at least two access points at the same time, whereupon thetraffic through the first access can be stopped. In other respects thefunctionality of the third embodiment of the method according to theinvention is similar to the functionality of any embodiment describedearlier.

The applications to use make demands on the access to use, e.g. asregards the transmission capacity and/or transmission errors. Hereby thecriteria may be changed according to the requirements of theapplications so that they suit the existing situation. On the otherhand, the characteristics of the chosen access point may provide theapplications with possibilities, e.g. for starting new functions. Thefunctionality according to the invention can be implemented fullytransparently from the viewpoint of the application used and from theuser's viewpoint or also in such a way that the chosen accesspoint/points and the possibilities provided by the chosen access pointsare reported to the application to be used and/or to the user, so thatthe application or the user may when he so desires utilize the newpossibilities provided by the access/accesses and/or adapt his operationso that it suits the access. The demands made by the application on thedata transmission can be determined from the protocol used by theapplication or from the QoS (Quality of Service) parameters establishedby the application, which define certain demands made on the datatransmission, or by providing the application with an interface, throughwhich the application may establish any routing criterion presentedherein. By reporting to the application the transmission capacityinformation of the access in use it is possible to perform such agradation of the various functions of the application that thetransmission capacity in use at each time is sufficient to ensure anormal operation of the application. E.g. transmission of e-mail fromthe application may be delayed until there is sufficient transmissioncapacity available for transmitting both the other traffic and e-mailmessages. When desired, the application may also be given reports on thecharacteristics of alternative available routes, e.g. on thetransmission capacity, so that the application is aware of any availableadditional transmission capacity, which its functionality may requirelater.

In a first alternative embodiment of the invention, the router islocated in terminal equipment TE, which may move from one place toanother and connect to the data transmission network when required. Forterminal equipment TE to connect to access points of the datatransmission network no new additional functions are needed at theaccess points or in the access protocols compared with the state of theart.

FIG. 6 shows the structure of terminal equipment TE according to theinvention at protocol level. When the Internet network relays databetween the host and terminal equipment TE, the terminal equipment usesTCP/IP protocols in the manner shown by the figure. The router joins theother functionality by way of the IP protocol. The user's data packagesmay be capsulated between the router of terminal equipment TE andgateway exchange GW using some state-of-the-art method, such as e.g.Mobile IP, in a second alternative embodiment of the invention, therouter is located both in terminal equipment TE and in gateway exchangeGW. Both these routers independently implement the functionality of theinvention in accordance with some embodiment described in the foregoing.

In a third alternative embodiment of the invention, the router islocated in gateway exchange GW, which routes the data transmission tothe terminal equipment at least by way of one access according tocriteria established in advance.

The functionality according to the invention may of course be used alsoif the data transmission network does not include any intermediarynetwork and gateway exchange, but the terminal equipment is connecteddirectly to the host through at least two access points.

The drawings and the description relating to them are only intended toillustrate the inventive idea. As regards its details the functionalityaccording to the invention may vary within the scope of the claims. Theinvention is especially suitable for use in transmission in the form ofpackages, e.g. in connection with a GPRS network, but also in datatransmission of some other kind. The invention is not limited to useonly in connection with the access points described above.

1. A method for routing a data transmission connection between terminalequipment and a host over a data transmission network, wherein a datatransmission network includes at least two access points for connectionof the terminal equipment to the data transmission network, the methodcomprising: establishing a criterion for a choice of an access point;evaluating access points according to said criterion; choosing at leasttwo of the access points which meet said criterion; and connecting datatransmission traffic simultaneously through the at least two chosenaccess points.
 2. Method as claimed in claim 1, further comprisingchoosing the access points meeting said criterion in the terminalequipment.
 3. Method as claimed in claim 1, further comprising choosingthe access points meeting said criterion in a gateway exchange. 4.Method as claimed in claim 1, further comprising establishing thecriterion for the choice of a transmission capacity of a datatransmission of the chosen at least two access points, choosing thetransmission capacity of each chosen access point according to a resultof the evaluation, and proportioning the data transmission between thechosen access points in relation to the chosen transmission capacities.5. Method as claimed in claim 1, further comprising evaluating theaccess points constantly.
 6. Method as claimed in claim 1, furthercomprising evaluating the access points at certain intervals of time. 7.Method as claimed in claim 5, further comprising evaluating the accesspoints by monitoring a quality of the data transmission.
 8. Method asclaimed in claim 1, further comprising giving reports to an applicationused in the terminal equipment on characteristics of the chosen accesspoints.
 9. Method as claimed in claim 8, further comprising adapting afunctioning of the application according to the reportedcharacteristics.
 10. Method as claimed in claim 1, further comprisingreporting characteristics of the chosen access points to a user. 11.Method as claimed in claim 1, further comprising establishing thecriterion from an application to be used.
 12. Method as claimed in claim11, further comprising choosing at least one access point meeting saidcriterion for the application.
 13. Method as claimed in claim 1, whereinsaid evaluating comprises evaluating the access points, in which theaccess points comprise at least one wireless access point.
 14. A methodof routing a data transmission connection between terminal equipment anda host over a data transmission network including at least two accesspoints for connection of the terminal equipment to the data transmissionnetwork, the method comprising: establishing a criterion for a choice ofa data transmission relaying capacity of the access points; estimatingthe access points in accordance with the criterion; choosing a relayingcapacity of each access point according to results of the estimation;and proportioning data transmission traffic between the access points inrelation to the chosen relaying capacities such that data transmissiontraffic is sent simultaneously through the at least two access points.15. Method as claimed in claim 14, further comprising estimating theaccess points according to a criterion in the terminal equipment. 16.Method as claimed in claim 14, further comprising estimating the accesspoints according to the criterion in a gateway exchange.
 17. Method asclaimed in claim 14, further comprising estimating the access pointscontinuously.
 18. Method as claimed in claim 14, further comprisingestimating the access points at certain intervals.
 19. Method as claimedin claim 14, further comprising estimating the access points bymonitoring a quality of a data transmission.
 20. Method as claimed inclaim 14, further comprising reporting characteristics of the accesspoints to an application used in the terminal equipment.
 21. Method asclaimed in claim 20, further comprising adapting an operation of theapplication in accordance with the reported characteristics.
 22. Methodas claimed in claim 14, further comprising reporting characteristics ofthe access points to a user.
 23. Method as claimed in claim 14, furthercomprising establishing the criterion from an application to be used.24. Method as claimed in claim 14, wherein said estimating comprisesestimating the access points, in which the access points comprise atleast one wireless access point.
 25. An arrangement for routing a datatransmission connection between terminal equipment and a host over adata transmission network, wherein the data transmission networkincludes at least two access points for connecting the terminalequipment to the data transmission network, the arrangement comprising:a router, located in the terminal equipment, configured to route a datatransmission through at least two access points simultaneously. 26.Arrangement as claimed in claim 25, wherein the router is configured_toroute the data transmission through the at least two access points, inwhich at least one of the at least two access points comprises awireless access point.
 27. An arrangement for routing a datatransmission connection between terminal equipment and a host over adata transmission network, wherein the data transmission networkincludes at least two access points for connecting the terminalequipment of the data transmission network, the arrangement comprising:a router, located in the terminal equipment and in a gateway exchange,configured to route a data transmission through at least two accesspoints simultaneously.
 28. Arrangement as claimed in claim 27, whereinat least one of the at least two access points comprises a wirelessaccess point.
 29. An arrangement for routing a data transmissionconnection between terminal equipment and a host over a datatransmission network, wherein the data transmission network includes atleast two access points for connecting the terminal equipment to thedata transmission network, the arrangement comprising: a router, locatedin a gateway exchange, configured to route a data transmission throughat least two access points simultaneously.
 30. Arrangement as claimed inclaim 29, wherein at least one of the at least two access pointscomprises a wireless access point.
 31. Terminal equipment configured to:connect to a data transmission network through at least two accesspoints; establish a criterion for a choice of an access point; evaluatethe access points according to said criterion; choose at least two ofsaid at least two access points, wherein at least two access pointschosen meet said criterion; and connect data transmission trafficsimultaneously through the at least two access points chosen in the stepof choosing.
 32. Terminal equipment comprising: connecting means forconnecting to a data transmission network through at least two accesspoints; criterion means for establishing a criterion for a choice of anaccess point; evaluating means for evaluating the access pointsaccording to said criterion; choosing means for choosing at least two ofsaid at least two access points, wherein at least two access pointschosen meet said criterion; and connecting means for connecting datatransmission traffic simultaneously through the at least two accesspoints chosen in the step of choosing.